The present invention relates to improvements in web forming machines and more particularly, machines that are well adapted to forming a continuous web of paper from a slurry of stock deposited on the surface thereof and dewatered through the wire.
In the high speed formation of paper, a stock slurry is commonly deposited onto a traveling fourdrinier wire with the slurry dewatering through the wire surface and the fibers forming a web on the upper forming surface of the wire. Essential to the formation of a good web is the random orientation of the fibers so that the web has good formation and the fibers have uniform distribution and orientation and interlock forming a paper web which is uniform in appearance and strength. Such uniformity is advantageous and beneficial to substantially all of the properties of the paper web in that it improves strength and appearance, receptivity to ink and makes it possible to form a web of good quality with shorter and less expensive fibers than are necessary if random orientation of the fibers is not attained.
Machine design efforts have gone to great length to attain the uniformity of distribution and direction of the fibers and to maintain this random orientation as the stock slurry is deposited onto the web. In a conventional fourdrinier machine wherein the stock is deposited onto the beginning of a forming zone on a fourdrinier wire through an open slice from a headbox, limitations are encountered in that differences in velocity between the traveling fourdrinier wire and the spouting jet of stock will affect the orientation of the fibers and they tend to cause them to align predominantly in the direction of wire travel, or to tend to shift to extend in a cross-machine direction. Such variations will affect the machine direction versus cross direction strength ratio of the paper and an objective in controlled operation of a forming machine is to control the MD/CD ratio usually to attempt to attain a ratio of unity which achieves what is known as a square sheet.
An object of the present invention is to provide a new method and apparatus for forming a paper web wherein the fiber containing stock slurry is distributed onto a traveling forming surface in a unique manner.
A further object of the invention is to provide a machine for forming a continuous web from a slurry of stock wherein the random distibution and orientation of the fibers is improved, and improved control is obtained over a range of speeds of the traveling forming surface.
A still further object of the invention is to provide a method and apparatus for forming a web on a traveling fourdrinier wire with improved means for distributing the stock onto the wire obtaining a greater control over the quantity of stock supplied to the wire and better control over the manner in which the stock is evenly distributed onto the wire for improved formation and better drainage.
Other objects and advantages and features, as well as equivalent methods and apparatuses which are intended to be covered herein, will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments in the specification, claims and drawings, in which: